1. Cuba. Egon G.Toward a Methodology of Naturalistic Enquiry in Educational Evaluation(Centre for the Study of Evaluation, UCLA, Los Angeles. 1978).
2. Guba. Egon G. and Lincoln, Yvonna S.Effective Evaluation: Improving the Usefulness of Evaluation Results through Responsive and Naturalistic Approaches(Jossey Bass, San Francisco, 1981).
3. Kirkpatrick, D. L. ‘Evaluation of Training’ inTraining and Development Handbook, eds Craig. R. and Bittel, L. (McGraw Hill, New York, 1967).